Yep, a code error searching for V4 collection.  IDonnO is correct, you have to check that reference.  And mariner has a point concerning the VSS by Bagginsbill.  That would be better for shading your V4 character than the Matmatic.  I have been playing around with VSS using the Nybras character from DAZ and I'm impressed with it.  When the VSS Pro is officially released, it will intergrate matmatic.  There is a VSS thread located elsewhere in the forum.